Effect of overexcitation limiters on power system long-term modeling

In this paper we analyze the dynamic performance of a power system with generators operating under rotor current limitation considering various models of takeover and summed-type overexcitation limiters (OELs). It is shown that in certain cases the field current limitation introduces slow generator dynamics that interact with long-term dynamic devices, such as LTCs, whereas in other cases the generator dynamics remain fast even after the limitation of rotor current. Equations suitable for a quasi steady state (qss) simulation corresponding to several OEL dynamic models are derived and the results are compared to those obtained by a full simulation.